Insider buying

I am novice investor who has owned PLT since February and purchased on a few occasions since then. My average price before distributions is about $5.97. One of the reasons why I bought this stock was the level of insider buying. I figured if management was putting their money alongside mine, it might a reasonable longer term bet.

My opinion has not changed concerning the long term prospects however I find it curious that management is has not made a recent purchase at these levels. They must have open or closed periods of time for insider trading. Does anyone know if management would be able to purchase units if they so desired? Or are they restricted from making other purchases at this time?